7/27/2019 Electrical Interview Questions Part 10

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8/21/13 Electrical Interview questions Part 10

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Q:What is the difference between Isolator and Circuit Breaker?

A:Isolator is a off load device which is used for isolating the downstream circuits from upstream circuits for

the reason of any maintenance on downstream circuits. it is manually operated and does not contain any

solenoid unlike circuit breaker. it should not be operated while it is having load. first the load on it must be

made zero and then it can safely operated. its specification only rated current is given.But circuit breaker is

onload automatic device used for breaking the circuit in case of abnormal conditions like short circuit,overload etc., it is having three specification 1 is rated current and 2 is short circuit breaking capacity and 3 is

instantaneous tripping current.

Q:what is boucholz relay and the significance of it in to the transformer?

A:Boucholz relay is a device which is used for the protection of transformer from its internal faults, it is a gas

based relay. whenever any internal fault occurs in a transformer, the boucholz relay at once gives a horn for

some time, if the transformer is isolated from the circuit then it stop its sound itself other wise it trips the circuit

by its own tripping mechanism.

Q:What is SF6 Circuit Breaker?

A:SF6 is Sulpher hexa Flouride gas.. if this gas is used as arc quenching medium in a Circuitbreaker means

SF6 CB.

Q:what is ferrantic effect?

A:Output voltage is greater than the input voltage or receiving end voltage is greater than the sending end

voltage.

Q: what is meant by insulation voltage in cables? explain it?

A:It is the property of a cable by virtue of it can withstand the applied voltage without rupturing it is known as

insulation level of the cable.